Manufacture of records for sound-reproducing machines.



R. L. GIBSON.

MANUFAOTURE OP RECORDS I'OR SOUND REPRODUCING MACHINES.

APPLICATION FILED AUG. 17, 1907.

Patented Dec. 14, 1909.

llllllllllill EE E lillllllllllll I MMIHHHINHBIB "w3 rs1 @osea ROBERT L. GIBSON, OF PHILDELPHIA, PENNSYLVANIA.

MANUFACTURE OF RECORDS FOR SOUND-REPRODUCING MACHINES.

Specification of Letters Patent.

Patented Dec. 14, 1909.

Original application filed June 14, 1907, Serial No 379,712. Divided and this application filed August 17,

To all whom .it may concern.'

Be it knon'n that I, Renner L. GIBSON, of the city and county of Philadelphia and State ofPennsylvania, have invented an Iniprovement in the il'lanufacture of Records for Sountl-Rcproducinq Machines, of which the phoue records, namely, those of disk form having'a spiral groove in their face for 0peratmga stvlus. of the sound box, two general methods of manufacture have been employed. The tirstof these relied upon the etching process, and consisted essentially of floating upon the surface of a polished disk of zinc a thin greasy or' waxy coating, such as may be produced by a Wax dissolved in alcohol or other solvent, and after subjecting the surface so produced to the `stylus of al recording machine vibrated in accordance with sound Waves whereby the spiral tracing so formed will expose' the zinc, etching the exposed surface to form a spiral groove having' lateral undulations which correspond to the tracing of the stylus. so produced is thenl cleaned .and subjected to an electroplating operation, such as employed in electrotyping, and an inverse matrix is produced which, after being` backed to strengthen it., maybe subsequently employed as a die from which to impress in hard rubber or equivalent compoundsa record groove which may be used in the reproducing machine, such as the ordinary gramophone. In this manner, duplicates from the master record may be, employed in reproduciug' the sound waves. Great objection, boivmer has always resulted from the fact that in any etching process, the lateral walls are under-cut owing` to the fact that the acid eats laterally as Well as vertically, and conserpiently 'the records produced under this process have notvloeen considered satisfactory, and the process has been super- The etched disky Serial No. 398,001.

seded. The second process, and which that commonly employed at the present time, comprises the following` steps: A disk is coated with a waxy compound, such as -metallic soap, capable of being engraved,

and after being carefully smoothed and leveled, the stylus of the recorder acting as an engraving tool is caused, through the rotation of the disk, to engrave a spiral groove therein .ot' even depth and with lateral undulating side walls. This engraved disk is then dusted with plumbago and subjected to an electroplating process by Which a matrix is produced having a raised spiral upon its surface; the said master matrix after being backed and strengthened is in a form capable of bein-g used Aas a die for reproducing in suitable earthy compounds resembling hard rubber, duplicate records suitable for use in connection with the reproducing machine, such as the ordinary gramophone. Ordinarily, this master matrix in copper, secured by the elcctroplating process, is not employed the die because it Would soon wear out, and as there would be then no way of securing an accurate duplicate (since the wax engraved disk would have been injured ordestroyed), iti has been customary after producing the first matrix in copper to employ the same to impress one or more additional wax tabletsivith the spiraligroove lines and to produce dubbed matrices from these Wax impressions by further electroplating, the dubbed matrices so produced being then employed as the dies in the duplicating processes employed later on in the commercial ulunufacturc.

l'n the first process above mentioned, in which etchiing,l was employed., it has also been customary to dub the matrix as desirable results Would not be secured by attempting to use the zinc disk after etching more than in the first instance. In such case, the copper matrix produced from the zinc was emplo ed to produce duplicate dies by the dubbing operations, which have universally been employed, introduced undesirable defects and multiplies existing detects which may have been inherent in the original matrix, into the commercial records which are produced from the dubbed dies, and this is important because the very slightest irregularity in the grooves will produce marked defects in the reproduction of sound, as is Well known to those skilled in the art.

The object of my invention is to overcome the existing objections in the manufacture of commercial records and to produce records in a commercial manner and form which shall be more accurate in their reproductions.

Generally stated, `my invention comprehends a record tablet produced by the following process: A polished surface of a rotating disk has a line-like layer of a sub-- stance of a plastic or fluid condition fed upon it through la stylus kept in a state of vibration by t e recording diaphragm of a recording machine, the layer being received Aupon the plate in the form of a spiral and in such a manner that it has undulations corresponding to the sound Waves. This substance may be forced through'the stylus un der great pressure, if so desired. 4The spiral layer thus deposited upon the surface of the disk is then employed with the disk as a mold or form upon which an electrodepof inal grooved u thereon.

sition of copper is made, the copper bridging over the spiral layer. When the proper thickness of copper is provided, it is then stripped from the disk in the form of a sheet and such ot the spiral layer as may ad-l here to the copper sheet is removed by suitable solutions, and the copper record so made forms a permanent master record. This metal record is a disk with a spiral groove in its surface which is in the most pert'ect form for reproducing sound by use ot' a gramophone instrument. Asit is the origcopper record and as the re corded spiral has been destroyed, it is not advisable -to use this master record as a matrix or die, and l therefore produce an electroplated disk which is a matrix in the form of a die by plating copper, nickel or other metal upon the surface or' this grooved metal record, producing thereby a matrix With a raised spiral corresponding to the original disk with the recorded spiral laid This matrix so produced may be stripped from the original grooved copper record, and, after being backed, it may be employed as a die from which to make duplicate record tablets -in suitable earthy composition resembling hardrubber, which may be directly employed in connection With the reproducing gramophone instrument.

the revolving disk of a material which was Whore the primary spiral was laid upon l i i come oxidized or coated 'inc uding the rope-like portions are sutiiciently hard to withstand reasonable pressure, the original disk so prepared may be employed to directly lake an impression ot the sound record in a. wax surface, and this may be electroplated similarly to elec,- trotyping, and the dies so produced employed for reproducing in earthy composi tion resembling hard rubber, 'as above. However, as in this case there is danger of ythe original record becoming destroyed by repeated use, it is preferable to produce an electroplated master record from which future dies may be reproduced, and this would be preferably done by preparinga copper reverse with the spiral groove by electroplating and employing said grooved metal master record for preparing any number ot` dies from which to make the commercial record tablets in earthy or hard-rubber-like compositions.

In case the spiral layer, laid upon the revolving disk under the action of the re corder, should be of rope-like torni, that is to say, its sides having under-cut portions adjacent to the metallic disk, then in that event. iY is customary to electroplate the'rec- Aord tablets so produced until there is a"A deposition of copper upon the plate and around the spiral. rope-like layer to the depth approximately to the middle et the rope-like layer, and then by i,nterruptingA the deposition and allowing the surface to be- Wi'th a solution of poor conductivity, and repeating the electro lating operation until the entire surface covered the outer or'upper layer of with copper, n

be stripped from the deposited copper may iirst or lower layer and after being flattened Y and suitably backed he employed as the grooved master metal record in the manner hereinbcfore referred to. lt is also evident that the lower layer of the deposited copper, coupled with thedisk, will form a groeved master metal record which may also e employed when cleared of the rope-like material, as a master metal record from which to make the dies. ln this ease the spiral would run from lefttoright instead oi right to left, and the turn-table with the record disk would have to be rotated in reverse direction. lt will be seen that in the manufacture ot' grooved record disks in this inanner, the grooves will be very smooth since they partake of the smoothness of the ropelikc or other layer deposited by the 'recording stylus. The result ot' this smoothness is the elimination oi' scratchy sounds in the reproduction of music orl words by the graniephone instrument and hun scratchy minds so objectionably dominate reprcnluctions from record tablets made by the processes iirst above referred to employing etching and engraving as the preliminary operations.

J-*ii'iotherA 4i'eature ci my invention the production of a record groove which is wider Y phragm et' the sound'box so as to be vihrated as we approach those portions of the spiral of smaller d .meterg and this is importanti because. of the more bluut character ot the stylus point of the reproducer. because oli w rar. when it reaches those portions ot' thespiral disposed more nearly toward the center of the disk. widening ot the groove in a lgradual manner is the result ot causing the n'iaterial by which the deposited spiral is made to be t'orced through the stylus point at a fixed rate and by the natural gradual changingr ot' the surface speed ot' the disk at the point ol depof ion of the material. This will he understood from the tact that where the rotation of the disk is uniform, theI spirals at those portions of the disk ot greater diameter .are naturally longer than those. portions of t-he spiral adjacent. to portions ot the disk of less diameter, as each of such spirals is produced in the same time, it is: evident that more material is deposited per linear inch upon the spirals of smaller diameter than upon the spirals of larger diameter, and hence will Hatten out to a wider condition with the smaller spirals than with the larger. 'lhe metal record subsequently produced from this master pattern will take on the same properties. The. saine results may be obtained by regulating the flow of the material when the speed ot the disk is uniform or varying' as desired.

My invention .also eomprehends details which. together with the features above specilied, will be better understood by reterence to the drawings, in which Figure l is an elevation illustrating' diagrammatically the manner of allowing; the spirals ot' the deposited material in the. operation otl a. recording instrument; Fig. 2 is a. cross section of a portion of the prepared master pattern; Fig. 3 is a similar cross section after the ldeposition of the copper preliminary to stripping; Fig. l is a cross section ot' the stripped matrix suitably backed; Fig'. 5 is a cross section corresponding to Fie'. 2 but in which the deposited material is in rope-like form; Fig'. G is a similar cross section showing;` the. manner of depositing' the eopper thereon inthe produetion ot the metal record; Fig'. 7 is a plan View otl a portion ot the master record bet'ore eleetroplating; and Fig, 8 is a cross section of a portion ot a die produced t'rom the n letaljgiec Jjrd.

is the motor mechanism ot a gramophone recordingr machine and while rotatingr the turn-table. B also causes the sound box l) to be traversed radially otl the turn-tabh` by the meelumieal feed screw l?. 'l`lf`e sounds to he recorded are delivered into the'. bell-mouthed reeeiyer E.

(t is a stylus which is supported in a yertical position and connected to the dia- The production ot' this.

tions.

thereby. llhis stylus is made like a tube with au exceedingly small orifice aty thel bottom. The point oit the stylus is 'held slightly above and out ot contactv with the metal disk C which is supported. upon the turn-table. or spindle of the motor A. The upper end of the stylus G may communicate with a reservoir l for fluid by a tiexi ble. tul'eefH ot any suitable character. The reservoir may be an open receptacle'or may be in the t'orin ot a cylinde' and plunger like a hydraulic ram as indicated at I where the tluid is dense. By applying `great pressure the material being` vforced through the, stylus may be quite thick or dense. Where a more ltuid material is employed. it may be incorporated with` a volatile solvent so that when laid u'pon the disk it will quickly set and harden. Substances from which the raised line may be formed may consist of a mixture of equal parts ot' carnahuba wax, shellac wax and tallow, or refined asphalt um, as examples. lathe apparatus shown, the

plunger l moving at a tixed speed will pro"u duce a givenconstant tiow at the stylus. To make this tlow a minimum the valve P in the escape pipe R from the reservoir allows a maximum escape into a veel E ot the material ot which the reservoir is charged. As the operation progresses the valve is gradually turned mechanically/'or otherwise so as to reduce the escape. of material into the vessel E. This valyemay be closed `gradually by a weight T which may be in the JForm ot a bucket supported by a spring V and gradually increased Vin weight l by the dropping ot water or other Huid from a tank X through a uozxle Y controlled by a 'alye Z. ln this way the gradual lowering of the weighted bucket turns the. valve l" and in tmu gradually restricts the escape ot the material with the result ot more ot it beiner `forced through the stylus upon tlnl rotating disk to thicken the line ot deposit. l'li desired. heat may be applied to the nirterial during the above operation by a burner or otherwise` as found most courenieut. Any other type ot' apparatus may be. employed tor laying" a thin stream of material upon the recording` surface. it

will now be understood that as the recording disk (l is being' rotated the stylus (l is layer otjnatf'eriahd which it' ot' a tluid'eonsistency'will' set in the 'form indicated at .l in Fig. 2` but. if of a more soli'dconsisteuey will retain a rope-like form as indicated at l in Fig; 5. 1 l y As the deposition ot' this layer is accom-- plished without practical resistance. to the vibrations of the. diaplnagn'i it is evident that the lateral undulatious ot the layer will contorni very accurately to the sound vibra- Tt. is also vident that the amplitude i caused to deposit upon its surface a spiral of these sinuosities or lateral undulations may magnified to any' degree desired by simply 'adapting the leverage of the stylus to meet the requirei'nents.

lifter the master record is made as indicated in Fig. it. is coated with. a layer of copper electrically deposited, lirst under very low voltage and later under higher groove in its surface as at li and this groove will be exceeding smooth and accurate to the sound waves which dictated its sinuosities This matrix may be used to reproduce sounds. or it may be employed from which to make dies (reverse) by eleetroplating; as indicated at Fig'. 8 which may oe used for duplicatii the records in compounds resembling ha 'd rubber or other suitable substances.

u Ris before explained, the speed of the disk )i on the recorder being uniform the surface speed under the siylr-.s point will be gradually reduced as the recording proceeds so that if the Yhuid is forced through the stylus at a fixed rate the deposited material J will be of gradually increasing width so that the ultimate groove L will .likewise be of grad- I aally increased width from the beginning; to

the end ofthe spiral g but slight. and gradnal this change that. it is hardly perceptible to the eye. This change. in the size of the groove enables the style or needle of the ruin-mince to more perfectly cooperate with the lgiron away of its point. lit the deposited material is in rope-like forni as indicated at J then the'electroplated matrix l can not be directly made because of the under-cut por- 'ille copper deposit. is performed in two opi-rathaus, as follows: The iii-st deposit is indicated at. l" in lllig. t3 andiexte'nds up to the largest diameter of the material J; thrlisk preimrcd then removed from the plating i alli and the surface of the copper allowed to oxidizc or rubbed with a solution sui-h as aicohol and oil to deadcn the tallic surface slightly, after which the k is pnt back in the bath and the second deposit l made to completely cover the rope-liifc pintions J. This latter deposit li; may then be readily stripped from the part l and backed as before described and illustrated in Wirf. 'l. lt will a so be seen that the plate vfnih the part K will likewise constitute a record tablet which will reproduce the original sounds.

liihile it is not. nece" iry that the substance of which the parte J and J are formed shall and compensate for the wearing' eases-i be condncivcof electricity they may be so formed or may be subsequently, and before plating, coated with plumbago as in electroplat'ing. As before pointed out, the parts .l J may be so hard when dried that they, in conjunction with the rlisk C may be used as the matrix or master die for dubbing in wax in the making of a copper duplicate for subsequent use in duplicating the record tablets.

Among the great advantages of my improved method of making matrix dies for the manufacture of commercial records may be stated-tirst,the form of the undulations are more accurate conformations to the sound 'waves than by engraving` or etching; second.- the groove in the commercial record tablet is very smooth and eliminates scratchy sounds, thus insuring pure reproduction; third,- the master die for reproducing' may be made economically without dubbing and its incidental fonrt-h,- the master grooved `record matrix is in copper and`hence durable; tifth,- defects introdncedby coating the record with graphite employed in engraved Wax records are prevented; sixth,- the record groove may have any magnitude of relative lateral undnlations or sinuosities desired for any fixed sound sol that the reproduced sound may be louder and more distinct than the original sounds; seventh,-the record-groove may be of gradually increasing width (and depth if desired) from beginning' to end of the record to suit the gradual blnnting` of the stylus point; eightln the durability of the record is increased because it, being formed without. material resistance to the esonnd waves, will have more `gradual curves in the sinuosities and the width of groove beingA `gradually widened prevents excessive friction between the stylus point and record; and nintlnthe tone of reproduction will be 'purer and more accurate .than Where etched or engraved records are employed.

ln all cases where the electro-deposition is made upon a surface coated with plumbago, such as now in general use., the platingv is in copper because a metal harder than copper. such as nickel, will not adhere sufliciently to prevent the curling tendency of the harder metal` but. in the case of my in vention l first produce my master record in copper and may then directly make my dies from it in nickel backed with copperthcreby producing the strongest character of die vv'ithont. any interposed dubbing l optirations.

While l prefer the making of the groove of gradually 'increasing width it is evident that-it may be made of the same. width by sin'ply increasing the speed of rotation of the turntable, or disk C so as to keep the surface speed of the latter relative to the stylus the same throughoutl the laying of the defects;

remain at saine speedand the 'pressure onv the material in the reservoir I may be gradually decreased, in which -case a gradually le'ssenedjquantity of material will` leave the stylus with each successive rotation of lthe v disk c.

By my improved manner of making a sound record, it is evident that instead of incorporating into the electroplated surface of the groove a texture corresponding to the irregularities of an engraved surface in wax, of which it is a counterpart, I am enabled to produce a groove by electroplating and whose surface has a texture which` is the v counterpart or inverse of a. surface texture of a congealed de osited iuidrsuchf as compound capable of ein'g made to ilowfby heat and pressure and setfby cooling, aandwhich has notbeen disturbed byanyobject-ionable engraving' or abradinggoperations. l.The surfacete'xture of 'the groove 'oit` 'iny record is, therefore, exceedingly ysmooth-j,and reproduces without the `obj'e,ationablej sounds which are inherent to. allrecords which` are made from engraved or etched 'surfaces'.--

I have described my' improvements in a ploying them for `.connnercial'v"reproduction of record tablets, but fido; not coniine myself t`o'v the details eitheras 'to composition of 4the layers J, J'f'orjofl-'the-materials of `which. the electro-depositedjmatrix is composed since it inaybeof` other metal than copper; neitberdo 'l restrict myself to the manner of causing a separation between the parts K K of the electro-deposited metal layers.

In this applicationl do not claim the apparatus for the manufacture of the master pattern, ner do claim the method of manufacturing `the master pattern, or master record, as these form subject matter of my original application, Sen No. 379,712 tiled June 14, 1907 hereinbefore mentioned, and of which this application is a division.

I also Wish it'to be understood that while Ihave described my invention Withspecial reference to the making of disk records, I do not conue myself thereto as my invention may be employed to the making of any type of record where a grooved surface is required.

Having now described my invention, what I claim as new, and desire-to secure by Letters Patent, is

1. As a new article of manufacture,- an original metal master sound record formed manner to indicate myfprefer'red 'way of em-` vof an electroplated disk with groove. y

2'. As'an article of manufacture, a metallic sound record tablet in which the record groove is of increasing cross section throughout its length.

3. As an article of manufacture, a sound, record tablet in which the'record groove-1s` of increasing width throughout its length.

a record 4. As an article of manufacture, a sound? record tablet in which the record groove is in spiral form of even depth and laterally undulating and of increasing width throughout its length.

5. A master record having a sound groove `of increasing width throughout its length.

6. A master pattern having araised ridge-like 4irregular line corresponding to sound Waves and having a cross section inz creasing throughout its length.

'7..s a new article of manufacture, an original nietalmaster sound record consist ing of an electroplated disk having a lat-` erally undulating groove of a Width at any point in its length greater than the width of the'groove from said point to oneend thereof andless than the width of the groove from said point to the other end thereof.

8. As a new article of manufacture,A an original metal master sound recordvconsisting of a disk formed of an electroplated mass having a laterally undulating gcove of across section widest at the top and of. a

depth slightly'less than its width and in which the width at any point in-its length is greater than the width of the said groove between saidpoint and one end thereof.

9. As a new article of manufacture, an, original master sound record formed of. an electroplated disk with a record groovewhose surface has an inverse texture to that of a pluinbago coated surface of a congealed depositedtluid as distinguished from an engraved or etched surface.

l0. A master pattern consisting of a' fiat plate and having formed thereon a spirally arranffed raised rid e-likc laterall undulating line corresponding to sound waves and' formed 'of av deposited waxlike material adhering tothe plate widest at the bottom adjacent to'the plate and rounded at the top 'and having a cross section corresponding to,

the cross section of the lfinished sound record groove in the record tablet to be made from said master pattern.

In testimony of which invention, I have hereunto set my hand.

ROBERT L. GIBSON. Witnesses:

R. M. HUNTER,

M. F. `Dmsconn 

